Gary Johnson, the Libertarian Party presidential candidate, who has struggled in recent weeks to recover from a gaffe in which he was unable to identify Aleppo, in war-torn Syria, appeared to fumble once more on Sunday when he said no one had been injured in two violent events in New York City and Minnesota over the weekend.

“Well, first of all, just grateful that nobody got hurt,” Mr. Johnson told CNN’s Brian Stelter in an appearance on the network’s “Reliable Sources.”

Mr. Johnson, a former Republican governor of New Mexico, has been an object of curiosity for younger voters, as has Jill Stein, the Green Party nominee. Some establishment Republicans who do not support Donald J. Trump have been drawn to Mr. Johnson and his running mate, William Weld. The two campaigns have also been a source of alarm for Democrats, who fear that a third-party threat could shake up results in the coming election.

On Friday, Mr. Johnson and Ms. Stein were dealt a blow when they were told that they would not be able to participate in a Sept. 26 presidential debate at Hofstra University after they failed to reach 15 percent support in five national polls.

It was unclear whether Mr. Johnson’s gaffes would hurt his numbers. In assessing debate eligibility, the Commission on Presidential Debates estimated that he had reached 8.4 percent and Ms. Stein had reached 3.2 percent.

On Monday, Joe Hunter, a spokesman for Mr. Johnson’s campaign, said the candidate had quickly issued a Twitter response saying that he had misspoken and meant to say no one had been killed. Soon after Mr. Johnson’s “Reliable Sources” appearance, the campaign also issued a statement to The New York Post that acknowledged the injuries.

“Regardless of the motivations for such senseless acts, they remind us that there are very real threats to our safety and our freedom, threats that must be dealt with realistically and firmly,” the statement read.